U.S. Olympic swimming champion Michael Phelps has been sentenced to 18 months' probation after pleading guilty to drunken driving.

Phelps was given probation before judgment Wednesday in Salisbury, Maryland. The court ruling means the infraction will be cleared from Phelps' driving record if he complies with the terms of probation. Phelps pleaded guilty to driving while impaired, and prosecutors dropped their charges.

The 19-year-old Phelps was fined $250 and ordered to pay $55 in court costs. He must attend a meeting sponsored by Mothers Against Drunk Driving, and must give speeches to students at three local schools by June 1, advising and warning them about the dangers of alcohol.